In a procedure of transmitting an uplink signal of a communication system, an eNodeB (eNB, base station) adjusts a TA (Timing Advance, timing advance) value of a UE (User Equipment, user equipment) according to an offset status of the uplink signal, so that each UE sends the uplink signal according to its adjusted TA value, and uplink signals sent by all UEs under the eNodeB can synchronously reach the eNodeB.
In a communication system with a CA (Carrier Aggregation, carrier aggregation) characteristic introduced, a UE may communicate with the eNodeB through multiple CCs (Component Carrier, component carrier) in an uplink or a downlink. In a general case, all uplink CCs of the same UE may share one TA value. Therefore, in the prior art, the eNodeB adjusts the TA value only by referring to a signal sent by any one of all the uplink CCs of the UE and supply the adjusted TA value to all the uplink CCs of the UE for use.
In a procedure of implementing that all the uplink CCs of the same UE share one TA value, the inventors find that the prior art at least has the following problem: in a practical application, offset status of all the uplink CCs of the same UE may not be completely the same, which results in that all the uplink CCs of the same UE cannot share one TA value. For example, when a frequency selection Repeater (repeater) or an RRH (Remote Radio Heads, remote radio unit) is deployed in a network, if a signal on one or several certain CCs of the UE is amplified by the frequency selection repeater or forwarded by the RRH and a signal on another one or several CCs is not amplified by the frequency selection repeater and not forwarded by the RRH, or signals on different CCs of the same UE are amplified by different frequency selection repeaters or forwarded by different RRHs, uplink CCs passing through one of the frequency selection repeaters (or RRHs) or passing through two frequency selection repeaters (or RRHs) separately cannot share the TA value, but uplink CCs not passing through the frequency selection repeater (or RRH) may share the TA value with each other, or uplink CCs passing through the same frequency selection repeater (or RRH) may share the TA value with each other.
The inventors find that, in a communication system with a frequency selection repeater or an RRH, an eNB cannot determine which uplink CCs of one UE may share the same TA value, so the eNB cannot normally provide a carrier aggregation service for the UE.